This castle at the mouth of the fjord was probably built by Valdemar the Great in the 12C and has been frequently modified. Its history museum includes a section on the 1864 war against Prussia, as a result of which the Danes lost South Jutland. The collections are on three floors. Queen Dorothy's Renaissance chapel (ground floor) houses a fine triptych and marble and alabaster baptismal fonts. The great ballroom on the second floor of the North Wing boasts a parapet and medieval machicolations.
Address:Sønderbro 1, 6400 Sønderborg
Price:70 dkk (-17 years old free of charge)
Jun-Sep: 10am-5pm; Oct and Apr-May: Tue-Sun 10am-4pm; rest of year: Tue-Sun 1pm-4pm